'I' is for 'Imps'

‘I’ is for ‘Imps,’ proud owners of the previous empire before the Human Age. Diminutive by conqueror-species standards, they are about crotch-height on a human. They began their existences in The Cracks far out west beyond The Uncanny Valley, where they were collected by gremlins as popular pets. Gremlins bred the imps mercilessly, crafting races without mouths, eyes or many of the internal organs the typical biological organism considers comfortable. Today, the surviving breeds of imps often require repeated surgery in order to successfully eat food.

After the gremlins destroyed themselves in a selfless effort at defining hubris, the imps seized their remaining technology for personal conquest. They had the additional benefit of naturally enchanted bones, particularly horns, which manifest in them not unlike acne and tumors in other species, and enable amazing feats of conjuration. They may be one tenth the body of a triclops, but they can shoot lightning at him, and this levels the playing field. 

Their feats of magic climbed in scale until they attempted to summon their transcendent ancestors, a tribe most people refer to as “demons.” The summoning went very successfully if your goals are to set half the world on fire. The Apocalypse of Demons sapped most people’s sympathy for any slavery the gremlins put imps through, which imps consider insensitive, because it cost them their empire. Post-empire, imps spend most of their time screwing each other over, since cooperating went so poorly.